Filters can be placed in blood vessels to catch thrombus carried in the flowing blood. Such filters have been used clinically for many years. Filters are primarily placed temporarily during a high-risk procedure. One of the problems with long-term placement of a clot filter is what happens to the thrombus after the clot thrombus been caught in the filter. Where a filter is placed temporarily, the thrombus typically is removed by removing the filter. However, a long-term indwelling filter is not easily removed.
Blood clots can be dissolved in patients that develop them; however, this is done with significant risk to the patient when aggressive thrombolytic drugs are used. Among the risks is the possibility that the clot can move to the brain and cause a stroke, or move to other parts of the body and result in an embolism. Thrombolytic drugs can be administered to the patient, and are sometimes effective in dissolving a clot in place. However, the thrombolytic drug enters the patient's bloodstream and thus can create a risk of a bleeding event, such as a hemorrhagic stroke.